Nervous System: Chapter 33

Which two sentences taken together provide the BEST evidence to support the idea that the organs of the central nervous system are insulated and safeguarded?

1. The nervous system as a whole is divided into two subdivisions: the central nervous system (CNS) and the peripheral nervous system (PNS).

2. Because they are so vitally important, the brain and spinal cord, located in the dorsal body cavity, are encased in bone for protection.

3. The brain is in the cranial vault, and the spinal cord is in the vertebral canal of the vertebral column.

4. Although considered to be two separate organs, the brain and spinal cord are continuous at the foramen magnum.

The nervous system is the major controlling, regulatory and communicating system in the body. It is the center of all mental activity including thought, learning and memory.

Which answer choice BEST supports the idea that the nervous system is a type of communication system within the body?

Millions of sensory receptors detect changes, called stimuli, which occur inside and outside the body. They monitor such things as temperature, light and sound from the external environment. Inside the body, the internal environment, receptors detect variations in pressure, pH, carbon dioxide concentration and the levels of various electrolytes. All of this gathered information is called sensory input.

Which word from the paragraph provides context clues to the meaning of the word "variations"?

Although each subdivision of the system is also called a "nervous system," all of these smaller systems belong to the single, highly integrated nervous system. Each subdivision has structural and functional characteristics that distinguish it from the others.

What does the author use the word "integrated" to mean?